Quick answer
Strength supports mining; Cash supports upgrades. The official description says both can be earned while offline, but no offline rate is verified here.
Two currencies, two jobs
Strength affects how comfortable mining feels. Cash is the conversion step that moves the pickaxe and upgrade loop forward.
Offline wording
The Roblox description says players earn Strength and Cash while offline. Rate, cap, and timer behavior still need playtest proof.
Practical loop
Train, mine, sell, upgrade, then repeat. If either Strength or Cash falls behind, the next depth push will feel slower.
Evidence boundary
Useful, but not overclaimed.
This page uses official Roblox data where available. Player-search topics are included only when they help answer a question safely.